A Compact Modeling Approach to Enhance Collaborative Design of Thermal-Fluid Systems

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Jason Stafford ◽  
David Newport ◽  
Ronan Grimes
Keyword(s):  
Boundary Condition ◽  
Collaborative Design ◽  
Initial Conditions ◽  
Numerical Models ◽  
Reduction Process ◽  
Electronic Equipment ◽  
Compact Model ◽  
Compact Modeling ◽  
Modeling Approach ◽  
Compact Models

This paper presents an approach for reducing detailed numerical models of electronic equipment into compact thermal-fluid models. These compact models have been created using network analogies representing mass, momentum and energy transport to reduce computational demand, preserve manufacturer intellectual property, and enable software independent exchange of information between supplier and integrator. A strategic approach is demonstrated for a steady state case from reduction to model integration within a global environment. The compact model is robust to boundary condition variation by developing a boundary condition response matrix for the network layout. A practical example of electronic equipment cooled naturally in air is presented. Solution times were reduced from ∼100 to ∼10−3 CPU hours when using the compact model. Nodal information was predicted with O(10%) accuracy compared to detailed solutions. For parametric design studies, the reduced model can provide 1800 solutions in the same time required to run a single detailed numerical simulation. The information generated by the reduction process also enhances collaborative design by providing the equipment integrator with ordered initial conditions for the equipment in the optimization of the global design. Sensitivity of the compact model to spatial variations on the boundary node faces has also been assessed. Overall, the compact modeling approach developed extends the use of compact models beyond preliminary design and into detailed phases of the product design lifecycle.

scholarly journals Numerical compact modeling approach of dispersive magnetoelectric media based on scattering parameters

2020 ◽  
Vol 33 (1) ◽  
pp. 73-82
Author(s):  
Milos Kostic ◽  
Nebojsa Doncov ◽  
Zoran Stankovic ◽  
John Paul
Keyword(s):  
Magnetoelectric Coupling ◽  
Chiral Medium ◽  
Compact Model ◽  
Dispersive Media ◽  
Compact Modeling ◽  
Scattering Parameters ◽  
Electromagnetic Parameters ◽  
Retrieval Method ◽  
Modeling Approach ◽  
Isotropic Chiral Medium

Z-TLM based compact modeling approach for dispersive media exhibiting magnetoelectric coupling is presented in this paper. Scattering parameters based representation of considered medium is created in a form of compact model by extracting effective electromagnetic parameters using a retrieval method, and implementing them into a non-uniform TLM grid. Proposed approach is illustrated here on the example of dispersive isotropic chiral medium modeling.

Development of Compact Thermal–Fluid Models at the Electronic Equipment Level

2012 ◽  
Vol 4 (3) ◽  
Author(s):  
Jason Stafford ◽  
Ronan Grimes ◽  
David Newport
Keyword(s):  
Boundary Condition ◽  
Multiple Scales ◽  
Flow Characteristics ◽  
Electronic Equipment ◽  
Compact Model ◽  
Electronic Systems ◽  
Fluid Models ◽  
Electronic Components ◽  
Detailed Model ◽  
Computational Fluid Dynamics Cfd

The introduction of compact thermal models (CTM) into computational fluid dynamics (CFD) codes has significantly reduced computational requirements when representing complex, multilayered, and orthotropic heat generating electronic components in the design of electronic equipment. This study develops a novel procedure for generating compact thermal–fluid models (CTFM) of electronic equipment that are independent over a boundary condition set. This boundary condition set is estimated based on the information received at the preliminary design stages of a product. In this procedure, CFD has been used to generate a detailed model of the electronic equipment. Compact models have been constructed using a network approach, where thermal and pressure-flow characteristics of the system are represented by simplified thermal and fluid paths. Data from CFD solutions are reduced for the compact model and coupled with an optimization of an objective function to minimize discrepancies between detailed and compact solutions. In turn, an accurate prediction tool is created that is a fraction of the computational demand of detailed simulations. A method to successively integrate multiple scales of electronics into an accurate compact model that can predict junction temperatures within 10% of a detailed solution has been demonstrated. It was determined that CTFM nodal temperatures could predict the corresponding area averaged temperatures from the detailed CFD model with acceptable accuracy over the intended boundary condition range. The approach presented has the potential to reduce CFD requirements for multiscale electronic systems and also has the ability to integrate experimental data in the latter product design stages.

scholarly journals A Rational Numerical Method for Simulation of Drop-Impact Dynamics of Oleo-Pneumatic Landing Gear

2021 ◽  
Vol 11 (9) ◽  
pp. 4136
Author(s):  
Rosario Pecora
Keyword(s):  
Numerical Method ◽  
Initial Conditions ◽  
Impact Load ◽  
Numerical Models ◽  
Landing Gear ◽  
Design Stage ◽  
Impact Dynamics ◽  
State Variables ◽  
Adopted Model ◽  
The Impact

Oleo-pneumatic landing gear is a complex mechanical system conceived to efficiently absorb and dissipate an aircraft’s kinetic energy at touchdown, thus reducing the impact load and acceleration transmitted to the airframe. Due to its significant influence on ground loads, this system is generally designed in parallel with the main structural components of the aircraft, such as the fuselage and wings. Robust numerical models for simulating landing gear impact dynamics are essential from the preliminary design stage in order to properly assess aircraft configuration and structural arrangements. Finite element (FE) analysis is a viable solution for supporting the design. However, regarding the oleo-pneumatic struts, FE-based simulation may become unpractical, since detailed models are required to obtain reliable results. Moreover, FE models could not be very versatile for accommodating the many design updates that usually occur at the beginning of the landing gear project or during the layout optimization process. In this work, a numerical method for simulating oleo-pneumatic landing gear drop dynamics is presented. To effectively support both the preliminary and advanced design of landing gear units, the proposed simulation approach rationally balances the level of sophistication of the adopted model with the need for accurate results. Although based on a formulation assuming only four state variables for the description of landing gear dynamics, the approach successfully accounts for all the relevant forces that arise during the drop and their influence on landing gear motion. A set of intercommunicating routines was implemented in MATLAB® environment to integrate the dynamic impact equations, starting from user-defined initial conditions and general parameters related to the geometric and structural configuration of the landing gear. The tool was then used to simulate a drop test of a reference landing gear, and the obtained results were successfully validated against available experimental data.

scholarly journals The Process of Stellar Tidal Disruption by Supermassive Black Holes

2021 ◽  
Vol 217 (3) ◽  
Author(s):  
E. M. Rossi ◽  
N. C. Stone ◽  
J. A. P. Law-Smith ◽  
M. Macleod ◽  
G. Lodato ◽  
...  
Keyword(s):  
Black Holes ◽  
Initial Conditions ◽  
Numerical Models ◽  
Binary Star ◽  
Tidal Disruption ◽  
Massive Black Hole ◽  
Accretion Flows ◽  
Simple Order ◽  
Order Of Magnitude ◽  
A Chain

AbstractTidal disruption events (TDEs) are among the brightest transients in the optical, ultraviolet, and X-ray sky. These flares are set into motion when a star is torn apart by the tidal field of a massive black hole, triggering a chain of events which is – so far – incompletely understood. However, the disruption process has been studied extensively for almost half a century, and unlike the later stages of a TDE, our understanding of the disruption itself is reasonably well converged. In this Chapter, we review both analytical and numerical models for stellar tidal disruption. Starting with relatively simple, order-of-magnitude physics, we review models of increasing sophistication, the semi-analytic “affine formalism,” hydrodynamic simulations of the disruption of polytropic stars, and the most recent hydrodynamic results concerning the disruption of realistic stellar models. Our review surveys the immediate aftermath of disruption in both typical and more unusual TDEs, exploring how the fate of the tidal debris changes if one considers non-main sequence stars, deeply penetrating tidal encounters, binary star systems, and sub-parabolic orbits. The stellar tidal disruption process provides the initial conditions needed to model the formation of accretion flows around quiescent massive black holes, and in some cases may also lead to directly observable emission, for example via shock breakout, gravitational waves or runaway nuclear fusion in deeply plunging TDEs.

Compact Modeling of Forced Flow in Longitudinal Fin Heat Sinks With Tip Bypass

2003 ◽  
Vol 125 (3) ◽  
pp. 319-324 ◽  
Author(s):  
C. B. Coetzer ◽  
J. A. Visser
Keyword(s):  
Pressure Drop ◽  
Heat Sink ◽  
Heat Sinks ◽  
Compact Model ◽  
Forced Flow ◽  
Compact Modeling ◽  
Transfer Coefficients ◽  
Wide Range ◽  
Laminar And Turbulent Flow ◽  
Improved Accuracy

This paper introduces a compact model to predict the interfin velocity and the resulting pressure drop across a longitudinal fin heat sink with tip bypass. The compact model is based on results obtained from a comprehensive study into the behavior of both laminar and turbulent flow in longitudinal fin heat sinks with tip bypass using CFD analysis. The new compact flow prediction model is critically compared to existing compact models as well as to the results obtained from the CFD simulations. The results indicate that the new compact model shows at least a 4.5% improvement in accuracy predicting the pressure drop over a wide range of heat sink geometries and Reynolds numbers simulated. The improved accuracy in velocity distribution between the fins also increases the accuracy of the calculated heat transfer coefficients applied to the heat sinks.

Towards Compact Modeling of Noisy Quantum Computers: A Molecular-Spin-Qubit Case of Study

2022 ◽  
Vol 18 (1) ◽  
pp. 1-26
Author(s):  
Mario Simoni ◽  
Giovanni Amedeo Cirillo ◽  
Giovanna Turvani ◽  
Mariagrazia Graziano ◽  
Maurizio Zamboni
Keyword(s):  
Physical Simulation ◽  
Quantum Circuits ◽  
Compact Modeling ◽  
Quantum Computers ◽  
Expected Performance ◽  
Classical Simulation ◽  
Spin Qubit ◽  
Compact Models ◽  
Standard Formalism ◽  
Definition Of

Classical simulation of Noisy Intermediate Scale Quantum computers is a crucial task for testing the expected performance of real hardware. The standard approach, based on solving Schrödinger and Lindblad equations, is demanding when scaling the number of qubits in terms of both execution time and memory. In this article, attempts in defining compact models for the simulation of quantum hardware are proposed, ensuring results close to those obtained with standard formalism. Molecular Nuclear Magnetic Resonance quantum hardware is the target technology, where three non-ideality phenomena—common to other quantum technologies—are taken into account: decoherence, off-resonance qubit evolution, and undesired qubit-qubit residual interaction. A model for each non-ideality phenomenon is embedded into a MATLAB simulation infrastructure of noisy quantum computers. The accuracy of the models is tested on a benchmark of quantum circuits, in the expected operating ranges of quantum hardware. The corresponding outcomes are compared with those obtained via numeric integration of the Schrödinger equation and the Qiskit’s QASMSimulator. The achieved results give evidence that this work is a step forward towards the definition of compact models able to provide fast results close to those obtained with the traditional physical simulation strategies, thus paving the way for their integration into a classical simulator of quantum computers.

A quantum wave based compact modeling approach for the current in ultra-short DG MOSFETs suitable for rapid multi-scale simulations

2017 ◽  
Vol 137 ◽  
pp. 70-79
Author(s):  
Fabian Hosenfeld ◽  
Fabian Horst ◽  
Benjamín Iñíguez ◽  
François Lime ◽  
Alexander Kloes
Keyword(s):  
Compact Modeling ◽  
Multi Scale ◽  
Modeling Approach ◽  
Quantum Wave

An Efficient Radial Basis Collocation Method for the Boundary Condition Identification of the Inverse Wave Problem

2018 ◽  
Vol 10 (01) ◽  
pp. 1850010 ◽  
Author(s):  
Lihua Wang ◽  
Zhihao Qian ◽  
Zhen Wang ◽  
Yukui Gao ◽  
Yongbo Peng
Keyword(s):  
Boundary Condition ◽  
Collocation Method ◽  
Exponential Convergence ◽  
Initial Conditions ◽  
Identification Problem ◽  
Iteration Scheme ◽  
Wave Problem ◽  
Noisy Input ◽  
Radial Basis ◽  
Convergence Study

A meshfree collocation method using radial basis functions is proposed to identify the information of the inaccessible part of the boundary in the inverse wave problem. Tikhonov regularization associated with L-curve criterion is introduced to handle the ill-conditioned resulting matrix originated from the noisy input data. The method of Lagrange multiplier is employed to derive the appropriate weights for the known boundary condition and additional measured condition to achieve the optimum convergence. Iteration scheme can be avoided in the collocation algorithm which ensures efficiency, and the convergence study shows the exponential convergence for the solutions of this inverse wave problem. Numerical simulations demonstrate that stable and highly accurate results can be obtained in the boundary condition identification problem even when high noise is involved in the additional condition, known boundary condition or initial conditions.

Boundary-Condition-Independent Compact Models

2014 ◽  
pp. 91-158
Author(s):  
Clemens Lasance ◽  
Mohammed-Nabil Sabry ◽  
Avram Bar-Cohen
Keyword(s):  
Boundary Condition ◽  
Compact Models
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